Introduction In this study we aimed to provide preliminary evidence on the safety and efficacy of the currently used ovine pasteurellosis vaccine in Ethiopia using clinical and pathological endpoints. Methods Twenty, conventionally reared, apparently healthy, seronegative male lambs, were randomly classified into two groups of 10 animals as “vaccinated-challenged” and ”unvaccinated-challenged controls”. The first group received 1 mL of the licensed Pasteurella multocida biotype A based vaccine subcutaneously while the second group received phosphate-buffered saline as a placebo. Following vaccination, lambs were monitored for one month for potential vaccine adverse reactions. Five weeks postvaccination, all lambs were immunosuppressed using dexamethasone, and intratracheally challenged with 5.2×10 9 CFU/mL live Mannheimia haemolytica A1 (clinical isolates). Then, all lambs were followed up for eight days for clinical examination and necropsied on the ninth day postchallenge for pathological investigation. Results There were no safety issues recorded during the study. In terms of clinical signs, lambs developed fever, depression, mucoid bilateral oculonasal discharge, coughing and sneezing regardless of their vaccination status. Fisher’s exact test between vaccination status and each clinical sign showed a statistically insignificant association ( p >0.05). The main pathological findings in both groups were pulmonary congestion, atelectasis, emphysema, and suppurative bronchopneumonia. Consolidation lung lesion score of +1 (5/10 of vaccinated, 6/10 of unvaccinated) and +2 (3/10 of vaccinated, 4/10 of unvaccinated) were recorded in a statistically indifferent manner among both vaccinated and nonvaccinated groups ( p >0.05). Discussion and Conclusion Collectively, the results suggested that the vaccine posed no safety concern and presumably lacks protective efficacy against local isolates. However, the study did not analyze antibody titer and their functionality using serum bactericidal assays. Further confirmatory studies could provide more evidence on the vaccine efficacy. Safety should further be assessed in a field setting involving a large number of animals to enable detection of rare vaccine adverse events.

Backgroundrumen disorder is responsible for huge economic losses in ruminants due to decrease in production and increase in expenditure towards treatment. Acidosis is one of the most ruminal disorders, characterized by changes in the rumen environment and leds to systemic acidosis. To correct this disorder, recent alternative trends in sheep rearing have led to the use of prebiotics, rumenotorics and probiotics as feed additives or treatment.Context and purposethis study was to evaluate and compares the therapeutic effectiveness of probiotics, a combination of probiotics with prebiotics, probiotics with rumenotorics and with the standard treatment under experimentally induced acidosis.Methodsthe experimental study design was conducted from September to May 2019. For therapeutic study 25 sheep were randomly divided into 5 groups with deliberately imposed ruminal acidosis as a group comprising of 5 animals each.Resultsacidosis was induced by an oral dose of 50 g/kg with wheat flour after 24-hour fasting. Four therapeutic regimes and negative control group were employed, I-Probiotics, II-Probiotics with Prebiotics, III-Probiotics with Rumenotorics and IV-Standard treatment (sodium bicarbonate) was adopted. Then, laboratory analysis of rumen fluid, physical parameters and hematological changes before and after treatment was carried out. From a comparison of each treatment groups with the control group to correct ruminal pH, the combination of probiotics with rumenotorics, the mean ± SD before treatment (4.96 ± .837) increased to (5.92 ± .54), (6.30 ± .41), (6.75 ± 0.34) after treatment, was statistically significant (p < 0.05, 0.024, 0.047, 0.002), from day one-day three, respectively, and the therapeutic regimens of probiotics with rumenotorics was highly significance compare with control group (p < 0.05, p = 0.001 & p = 0.000) improved heart rate and respiratory rate at day three after treatment and the mean PCV value of treatment Group III was 38.00 ± 6.819 before treatment changed to 34.60 ± 5.367, 29.80 ± 6.261 and 24.80 ± 10.134 after treatment, were statistically significance (p < 0.05, p = 0.003, p = 0.02 &0.006) from day one-day three, respectively.Conclusionthe present study was concluded that probiotics with rumenotorics administered together were the most successful therapeutic regimen for improvement of ruminal acidosis. Therefore, in this experimental study for the treatment of acidosis, it has been recommended that use of probiotics with substrate is the promising alternative.

Background Acidosis is one of the most common rumen diseases characterized by changes in the rumen environment and the circulatory system. Recent alternative trends in rearing small ruminants have led to the use of probiotics, rumenotorics and prebiotics to treat acidosis in animals. Purpose This study aimed to evaluate the efficacy of probiotics and the combination of probiotics with prebiotics and probiotics with rumenotorics for the treatment of acidosis in sheep. Methods This experimental study was conducted from September 2018 to May 2019. For the therapeutic study, 25 sheep were randomly divided into 5 equal groups. Acidosis was induced by an oral dose of 50 g/kg with wheat flour after a 24 hour fast. Four regimens of therapy were employed: PT probiotics, PPT probiotics with prebiotics; PRT probiotics with rumenotorics and standard ST treatment were adopted. Before and after therapy, laboratory analyses on rumen fluid, serum analysis, physical signs, and hematological changes were conducted. Results When probiotics were combined with rumenotorics (PRT), the mean standard deviation of rumen pH at day zero was 4.96±0.837 (PRT). Rumen pH improved from day one today three to 5.92±0.54, 6.30±041 and 6.75±0.34, respectively. The change in rumen pH was statistically significant after treatment on day 3 (p=0.002). The therapeutic regimens of PRT had improved heart rate and respiratory rate after treatment and the change was statistically significant (p=0.006 and p=0.000) compared to the control group. The PCV of the PRT treated sheep was also improved. Conclusion Probiotics with rumenotorics were the most successful therapeutic regimen for the treatment of ruminal acidosis in sheep. Therefore, the use of probiotics with rumenotorics is the promising alternative for the treatment of acidosis.